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Biomedical subjects

T M Young

Publications and source records attributed to T M Young.

At least 37 records · Page 2Linked to original sources
PubMed1994

Airway management in dental anaesthesia.

Ninety patients were allocated randomly to three groups for airway maintenance during paediatric outpatient dental extraction: laryngeal mask airway, nasal mask with nasopharyngeal airway, or nasal mask alone. Surgical access was better with the laryngeal mask. Airway maintenance was easier with the laryngeal mask than the nasopharyngeal airway, and both were better than nasal mask alone. No patient became hypoxic with the laryngeal mask, five patients became hypoxic with the nasal mask and two with the nasopharyngeal airway at corresponding periods, although the differences were not statistically significant. The laryngeal mask airway is recommended for paediatric outpatient dental anaesthesia.

Airway Obstruction↗
PubMed1993

Effects of orthodontics on the facial profile: a comparison of changes during nonextraction and four premolar extraction treatment.

Cephalometric radiographs were used to examine soft tissue profiles of 198 orthodontic patients treated with full fixed appliances without extraction of any permanent teeth. Records were selected at random from five sources: cases treated by a Tweed Foundation instructor using the Tweed technique, patients treated with the Begg appliance, patients treated in one of two different practices with pretorqued, preangulated edgewise appliances, and patients treated in two stages with a functional appliance followed by full fixed edgewise appliances. The criteria for selection of cases and the methods of data collection were designed to allow comparisons with data collected by Drobocky and Smith on patients treated with extraction of four first premolars. Although the mean value of soft tissue changes were smaller in the nonextraction patients, the variability of these changes were generally as great as in the four premolar extraction cases. In addition, the percentage of undesirable facial changes was similar in the extraction and nonextraction samples. The results provide additional evidence that it is simplistic and incorrect to blame undesirable facial esthetics after orthodontic treatment on the extraction of premolars.

Analysis of Variance↗
PubMed1990

Channel fluctuations induced by membrane attack complex C5B-9.

The assembly of complement (C) components C5b-9 in membranes results in the formation of transmembrane lesions. The C9 component has been shown to be mainly responsible for formation of the ultrastructurally visible tubules associated with C5b-9 complexes. Several studies have disputed the role of C9 polymerization in C-mediated cytolysis on the grounds that C5b-9 lyses cells in the absence of tubular formation. Here, C5b-9 complexes were reconstituted into high-impedance planar lipid bilayers and shown to form channels which are heterogenous in size. The smallest channels had unitary conductances of 15 picoSiemens (pS) in 0.1 M NaCl. The closing of these channels showed voltage-dependence at membrane potentials exceeding 40 mV. These channels were more cation-selective, with K+ ions being favored over Na+. The 15-pS channels described here are much smaller than the channels attributed previously to either C5b-9 or polymerized C9 complexes but resemble channels formed by the C9b fragment, which does not polymerize into tubules. These results indicate that C5b-9 complexes are capable of damaging membranes by forming initially small ion channels which then aggregate in the membrane to form tubular lesions with much larger conductances. Like C5b-9, C5b-8 also increased membrane permeability. However, this increase in membrane conductance could not be resolved into single channels, suggesting that C5b-8 may induce membrane leakiness by perturbing the packing of membrane lipids, whereas addition of C9 results in authentic production of ion channels.

Cell Membrane Permeability↗
PubMed1990

Therapeutic case advocacy: a model for interagency collaboration in serving emotionally disturbed children and their families.

A model for the creation of a system of care for emotionally handicapped children and their families is presented. The model delineates a framework for modifying environments and for identifying the clinical skills necessary to do so. Coordination of the efforts of both formal organizations and natural support systems is seen as an essential component of the proposed system.

Affective Symptoms↗
PubMed1990

An evaluation of combining thiopentone and etomidate for the induction of anaesthesia.

The characteristics of three combinations of thiopentone and etomidate [in the ratios of thiopentone (mg):etomidate (mg) of 5:1, 13:1 and 25:1] have been compared with the individual agents alone for the induction of anaesthesia. The incidence of pain on injection and abnormal movements was less with the combination containing the highest ratio of thiopentone to etomidate, when compared to etomidate alone. The mixtures did not otherwise confer any advantages over the individual agents.

Adult↗
PubMed1984

Protein-mediated intermembrane contact facilitates fusion of lipid vesicles with planar bilayers.

Fusion of phospholipid vesicles with planar bilayer membranes occurs provided there is an intermembrane contact, which can be mediated by phospholipid-binding proteins, even in the absence of calcium. The firm attachment phase is then followed by the osmotically-driven fusion. These results show that hydrophobic proteins (not necessarily Ca2+-binding proteins) may enhance fusion by promoting contact of membranes. Such proteins may operate synergistically with Ca2+ to reduce the threshold concentration of Ca2+ needed for fusion of biological membranes. Protein-mediated intermembrane contact resulting in fusion may play a crucial role in the regulation and catalysis of biological fusion events.

Calcium↗
PubMed1982

Characterization of a membrane pore-forming protein from Entamoeba histolytica.

We describe the partial purification and characterization of a pore-forming material (PEM) from Entamoeba histolytica. The formation of ion channels by PFM was examined in three systems. (a) PFM depolarizes J774 macrophages and mouse spleen lymphocytes as measured by [3H]TPP+ uptake. (b) PFM induces rapid monovalent cation flux across the membrane of phosphatidylcholine-cholesterol vesicles. (c) PFM confers a voltage-dependent conductance to artificial planar bilayers, which is resolved as a summation of opening of individually conducting steps of 67 pS in 0.1 M KCl. Monomers of PFM are functional; however, a preferential aggregation occurs in the planar bilayer. Activity is pronase, trypsin, and heat sensitive and is stable between pH 5-8. PFM is not secreted by unstimulated amoebae but after exposure to the calcium ionophore A23187, concanavalin A, and E. coli lipopolysaccharide, 5-10% of the total cell content of PFM is released into the medium within 5-10 min. High-performance gel filtration results in an approximately 1,000-fold purification of PFM and gives an Mr of 30,000. This protein may play a role in the cytotoxicity mediated by E. histolytica.

Animals↗
PubMed1978

A throat spray.

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Aerosols↗